Hantkenina liebusi

Original Description"Test planispiral, compactly coiled, almost completely involute, bilaterally symmetrical. Contour oval, elongate at the apertural end. The test consists of two whorls, usually only the last one visible, with 5-6 chambers; in young specimens the chambers of the first volution are clearly visible. Chambers slightly inflated, internal end more vaulted, outer angle extended into a hollow acicular spine. The spines are mostly long and thin, but in some specimens they were found to be rather stout and granulate.
"The periphery is lobulate, mostly more or less rounded, but may be slightly angled. The size of the chambers increases gradually, except in the last one which is almost twice as large as the preceding one. Chambers separated by rather deep sutures. The chamber walls are calcareous and mostly thin, in some cases slightly thickened, transparent and smooth, finely perforate. The aperture is situated at the inner margin of the chamber and consists of 3 parts; an upper arch and 2 basal lateral lobes which are broken in most of the specimens. The margin of the aperture is furnished with a thin plate-like lip, projecting in the direction of coiling. The diameter of the shell is 0.48 mm.

References:

Shokhina, V.A., (1937). The genus Hantkenina and its stratigraphical distribution in the north Caucasus. Problems of Paleontology: 425-441.